TCA Cycle: Succinyl-CoA Synthetase

Question 1

What is another name for succinyl-CoA synthetase?

Answer 1

succinate thiokinase

Question 2

What reaction does succinyl-CoA synthase catalyze?

Answer 2

It couples the cleavage of high energy succinyl-CoA to synthesis of high energy GTP

Question 3

The synthesis of what high energy nucleoside triphosphate is the cleavage of succinyl-CoA coupled to?

Answer 3

GTP

Question 4

True or false: GTP is equivalent to ATP.

Answer 4

True

Question 5

What are the three reactions in the succinyl-CoA synthase step of the TCA Cycle?

Answer 5

1) Succinyl-CoA reacts with Pi to form succinyl-phophate and CoA
2) A phosphoryl group from succinyl-phosphate is transferred to the histidine residue on succinyl Co-A synthase, releasing succinate.
3) The phosphoryl group is transferred to GDP to form GTP.

Question 6

How is the high energy of succinyl-CoA conserved and passed on in the reaction catalyzed by succinyl-CoA Synthetase?

Answer 6

As GTP

Question 7

At what step in the TCA Cycle is one acetyl equivalent completely oxidized to 2 CO2, 2 NADH, and 1 GTP?

Answer 7

Following the succinyl-CoA synthetase step.